Centrifugal separator



Patented May 30, 1939 UNITED STATES CENTRIFUGAL SEPARATOR Application December 9, 1937, Serial No. 178,875

3 Claims.

In an application for patent led by me August 26, 1935, Serial No. 37,895, there is disclosed a process and machine for separating high viscosity cream from skim milk, wherein the separated cream and skim milk outow from a centrifugal separator into and through separate stationary passages closed to the atmosphere. In the cream discharge passage is established a regulable predeterminable yielding mechanical pressure tending to maintain a definite resistance to outflow of cream. In the machine oi said application the cream and skim milk are discharged from the bowl through channels formed in the bowl neck, and flexible and elastic packing rings surround the bowl neck and seal the stationary skim milk and cream outflow channels.

In such a separator it is important to maintain the sealing rings immersed in liquid during the time that the separator is rotating. So long as whole milk is being fed to the separator this condition is maintained without special means to provide for it, since the outilow passages are lled with liquid. When, however, feed of liquid to the separator is discontinued, discharge of liquid from the separato-r ceases. While the stationary skim milk channel remains filled with liquid and consequently the sealing means therefor remains in contact with liquid, a partial vacuum is established at the cream outlet, thereby preventing accumulation of milk in the stationary cream outflow channel. The sealing ring around the upper end cf the bowl neck is thus unprotected by liquid and the separator bowl runs dry at this point, causing rapid and serious deterioration of the sealing ring.

The object of my invention is to maintain this sealing ring, as well as the other sealing rings, immersed in liquid during temporary stoppage of the supply of whole milk and while the separator continues its rotation.

While the invention may be thus adapted and applied to the specific construction of closed centrifuge above described, it is obvious that it may be adapted and applied to other types of closed centrifugal separators wherein similar conditions may arise.

A preferred embodiment of the invention as applied to the type of closed centrifuge disclosed in my said application for patent is shown in the drawing, which is a vertical sectional view of the upper part of a separator bowl and the stationary flow passages associated therewith.

In the separator bowl a whole milk is separated into cream and skim milk. Both separated constituents are discharged through the bowl neck b, the skim milk through the passages c and the cream through the passage d.

Surrounding the bowl neck b is a stationary skim milk receiving and discharge chamber e, mounted upon which is a block .r having a central cream receiving chamber f. Between the skim milk chamber e and the bowl neck is a packing ring g of flexible elastic material which seals the skim milk chamber from the atmosphere around the bowl. Other similar packing rings h, h seal the skim milk chamber e and cream chamber f from communication with each other.

Mounted upon the cream receiving chamber f is a cream outilow cylindrical chamber k. The bottom of this cylinder is dished downward and provided with orices z' through which cream ows into thev cylinder from chamber f. Extending vertically through cylinder 7c is a valve stem m, the lower reduced end of which is guided in the dished-down central part of the bottom of the cylinder. The annular shoulder at the upper end of the reduced lower end portion of valve stem m overlies a valve disc n which rests on the bottom of cylinder 7c, the latter acting as a valve seat. The upper end of the valve stem m rests against a headed pin p extending through the top of cylinder 7c. Across the upper end of cylinder 7c extends a diaphragm o, the peripheral portion of which is confined between the body and top of the cylinder and the central portion of which is confined in an annular groove in valve stem m near its upper end. By means of a spring s, the valve stem m and valve n is forced down against the valve seat. The pressure of the spring s may be varied to regulate the fluid pressure required to lift valve n and force cream from chamber f into the valve cylinder 7c. The greater the pressure of the spring, the greater the resistance to flow of cream and the more concentrated the cream. Variations in the resistance to flow of cream through the valve, which variations in the pressure head in the cream discharge tends to produce, are prevented by the diaphragm o; that is, pressure of the head of cream against valve n tending to increase resistance to flow is counteracter by the pressure against diaphragm o tending to decrease such resistance.

The above described construction for regulatW ing the density of the cream is a specific embodiment of the invention described in my said application, to which reference is made for a more detailed description of the mode of operation.

In the normal operation of the separator, whole milk is fed continuously into the bowl and skim milk outows continuously through the discharge e and cream outflows continuously through the chamber f and cylinder lc. 'I'he packing rings g, h, h' are thus continuously submerged in liquid. It will be understood that during such operation there is a back pressure on both the skim milk and cream. The back pressure on the skim milk may be assumed, solely for the purpose of illustrationftobe two pounds and that on the cream to be twelve pounds. uWhen feed of lwhole milk to the separator is interrupted, while the bowl continues to revolve, the outflow of the separated The bowl and-theskim milk constituents ceases. discharge remains lled, but a partial vacuum is created in the cream receiving'chamberf and it is emptied of liquid. The top of `the "bowlneck, therefore, runs dry. Owing to the highspeed'of the bowl, a very considerableamountaofihea'ths generated at the bearing between the bowlV neck and the packing h, which causes rapid and serious 4deterioration: of the-packing.

In a construction embed-ying -myfinvention this condition. is prevented by the following expedient. Formed` in -the f rameienclosing the skim l milk `discharge chamber e is a valve .chamber u'havin'gfan openingA a in :its =bottomf1communicating with the skim milk discharge chamber.Y 1A-vaflve-Uisrseate'd over. thisopening. It is .f'provided :wit-h- Wings 'u' by whichit is guided. vAehannel fw, formediin Ythe-v block a', connects valvercha-mberfu -withvthe cream receivingehamber'f.

In the normal `.operationof the machine the fsuperior-pressure. in the` creamfrecei-ving.chamber f-is operative-.uponwalvefvwtohold it omits seat. IWhen, however; inflowfof -whole milk tothefseparator. isf-interruptedthe pressure Ain -fthefcream receiving chambenf. drops belowthati inthe `skim milk receiving` chamber e. :Valve-i: Yis .them lifted from-.its seatfand allow of .milk is established fromhamber through-valve chambe1\u,-:chan nel cream. receiving- Achamber rfand. krpassagefd back. tothebowl. rTherebythefpack-ing `h is maintained submerged-in liquidvand .the=bowl, without inflow of wholemilkVmay'-continuato revolveat high speed .without injury toranyoi"V the-sealing devices.

It will ,be understoodthat-.theinventionfis not -limited l to the operation .of thegmachine .as .a milk-cream separator. It willy alsobe understood that .centrifuges operating von a different principle4 but 'having discharge passages sealed v.by packing .which shouldnotbe allowedto rundry may, 'upon'.interruptionof"feed of liquid tolthe separator, ldevelopv conditions which maylperm'it of the 'adaptation' thereto of vmy invention.

lWhat I claim andv desire to 'protectbyl Letters Patent'is:

1.1`In a centrifugal "separator comprising a -`rotarybovvl having outlet passages for ihe'avier 'arfdlighter constituents, stationary chambers 4intoiwhich-said constituents 'are adapted to respectively f discharge, a' lighterliquid densityI reg- 'ulatin'g"valve fbeyonol" the receiving 'chamber ifor lighter liquid"and"which' lmaintains la vsuperior pressure thereinf :during normal' operationl f the separaton' and f' e'x'ible .packing'means lengaging thebo'wl-necklandseaiing 'saidicha'mbers aridz 'submerged in outflowing 'liqui'd'during'fthe fino'rr'nal -operation"of the sep'arato'': the-improvement ffor "liquid therethrough into the lighter liquid charnber-tof-thereby maintain said packing device submerged in liquid.

"2.In a'centrifugal-separator comprising a bowl having valoowlneck:provided with an outlet passage Yfor heavier separated liquid terminating vbelowfitsupper'end and an outlet passage for lighter .separated liquid terminating above the iirsturarned outlet, a frame enclosing a lower 'receiving' vchan-rb er -lcommunicating with the iirst named-..c'utletfpassagerand an upper receiving Icham-berrcommunicating i with the second named Fout'let'fpassage, a i 'lighter f liquid `density reguiatingfvalvebeyondthe upperf'chamber and vwhich 'maintains `a superior-pressure therein iduring normal operation or the separatcLand flexible packing'means between the-bowl neck andthe frame.includ-ing Ya packing device Vsealing the upper". chamber; .theimprovement i or maintaining submergedrinfliquid saidpacking device when feed -of-.liquidto the separatorbowl is interrupted, whichscomprises aivalve chamber between-'and *communicating with :said receiving chambers and a-v-alve in the 'valve chamber which is operable by the superioripressureinr the=upper-re ceiving. chamber to close communication'.between said-receiving chambers .when the pressure in the:upperreceivingcharnber exceeds 'that' in the lower-receiving-cha-mber tand-.which is operable by '.thes'uperfior pressure in .the heavier liquid chamber ltoppen such communication 4 when the relative'prcssures= in the receiving-chambers are reversed.

A centrifugal'rnach-ine comprising va cen- .trifugalybowl having outlet passages for.Y heavier .fand'clighter separated constituents, stationary chambers into which said constituents are :adapted-tobedischargeiipackingmeans engaging the bowl andi-.sealing :the respective v chambers and submerged bythe liquid therein', a liquid density regulating'-rneans.operable-during feed to the bovvlrin they normalcperationof the separator, to-imaintain4 azhigher. pressure in :one receiving chamber than in the other, said chambers being so-'tarranged 'as to .reverse Asaid pressures -when saidv feed visvinterr-upted, means .i providing .apassage-exterior' to the-bowl between -said chambers, Va valve, int-said".passage-'opposed faces Vci which are subjected to the pressuresin-the respective vchambers andi-which, while said ldifferential pressure during.normal-:operation-of the bowl is maintained, Aisl held in position toY close Vsaid `pas- 'sagezand which, when fthe.` relative pressures in thestwocharnbers is reversed, is movedinto position to open said passage and, by thus vestablishing a liquid flow (therethrough, maintaining the vpacking meansrsubmergedrin liquid.

f CYRUS- HOWARD HAPGGOD. 

